The seventh planet of the solar system, Uranus, has always had an unusual axis which set it apart from other planets, but not enough research was conducted to explain it more in detail. A study earlier this year suggested that the planet’s shape and many of its properties were impacted by a collision with an object twice as big as Earth. Now some new analysis supports that research and sheds light on the differences between Uranus’ axis and those of other planets.
Uranus is an ice giant, and its axis is titled at a 98-degree angle, as opposed to all other planets, which rotate around a vertical axis relative to their orbits. Because of how much Uranus is tilted, researchers believe it rotates on a horizontal axis. The newest analysis suggests that this unusual axis was caused by a massive collision. Researchers also believe the impact may have caused the planet’s icy outer layer and exceptionally freezing temperatures.
An international team of scientists led by astronomers from Durham University studied Uranus’ axis and tried to determine how it came to be horizontal and how this unusual tilt has impacted its evolution as a planet. The research was published earlier this year in The Astrophysical Journal.
The team created the first high-resolution computer simulations which show different massive collisions which could explain how the planet evolved. The team suggests that the planet was tilted after a collision with a massive object believed to have been a young protoplanet composed of rock and ice. They suggest the collision occurred around the time when our solar system was just forming, which scientists believe was over 4 billion years ago.
Durhama PhD researcher Jacob Kegerreis and his team recreated the analysis and built an improved-resolution computer simulation which shows a huge object colliding with the planet, likely causing Uranus’ axis to tilt 98 degrees. The collision is believed to have affected the planet’s spin, magnetic field and how heat is distributed across the planet. Researchers say the simulation shows how the collision likely looked 3 billion or 4 billion years ago.
They say the collision likely affected the formation of ice layers on the planet, which keep its heat locked in its core rather than leaking onto its surface or into its atmosphere. Moreover, Uranus is the only planet which doesn’t leak heat from its core, and temperatures on its surface can fall as low as -371 degrees Fahrenheit at its coldest points.
Researchers say the catastrophic collision they believe shifted Uranus’ axis in this odd manner likely caused the planet’s larger moons and rings, which are aligned with its rotation and make the planet even more unique in our solar system. Nevertheless, researchers want to learn more about the planet, given that the last close encounter with the planet was when the Voyager 2 spacecraft passed by in 1986.